An automobile is an important traffic means in the modern society. It is a good thing to buy and own a car, and to conveniently go any place by driving. However, almost all the car owners have the bothersome problem of guarding the car against theft. A car thief would try different ways to steal a car, such as destroying the car lock, preparing a master key, destroying the door handle, driving away a car having the key left therein, etc. According to official investigations, an experienced thief needs only five minutes to steal a car. However, most car thieves would not take a risk and spend a lot of time to steal a car having an antitheft system mounted thereon.
Therefore, there are various types of auto antitheft systems developed and available in the market, and these antitheft systems generally produce a deterrent effect by emitting a warning sound at the instant the car is invaded by a thief. The currently available auto antitheft systems are different in their performance and effect. The auto antitheft systems and remote-controlled power locks in early stages are generally controlled using a remote controller. However, an advanced original equipment antitheft system for car as shown in FIG. 6 has been developed to save a user the trouble of carrying a remote controller or carelessly leaving the remote controller or a key in the car. In the antitheft system shown in FIG. 8, a numeral keypad 2a is provided near a door handle 3a. A user may conveniently enter a code by pressing numbered keys 22a on the keypad 2a to release or enable the auto antitheft system without the need of carrying the remote controller. The auto antitheft system with the keypad is therefore a convenient, advanced, and humanized design.
While it is very easy to provide such keypad on the door of a car as original equipment thereof, it is quite troublesome to additionally mount the keypad on the door of a car as an after-service because it is necessary to drill a hole on the car door for mounting the keypad, and then electrically connect the keypad to a main controller mounted in the car. And, most car owners are not willing to drill holes on their new cars for mounting the keypad.
A currently available solution best for this problem is to bond a wireless keypad to a car door, so as to avoid drilling on the car door and therefore attract more customers to mount this type of antitheft system. The wireless keypad is received in a case and internally provided with a key circuit, a battery, and a wireless transmission circuit. However, the wireless keypad bonded to the car door tends to be easily stolen by a thief or separated from the car door due to car washing or vibration in driving.
It is therefore tried by the inventor to develop an antitheft system with clip-on wireless keypad to overcome the above-mentioned problems.